CERN Beamline for Schools (BL4S)

An international CERN competition in which teams of high-school students design their own particle-physics experiment. Winning teams get the opportunity to carry out their experiment using a real accelerator beam at CERN or another participating research laboratory. In 2026, 712 proposals involving 4,051 students from 89 countries were submitted.

Authentic research experience; development of an original experimental proposal; physics and mathematical reasoning; teamwork; exposure to particle physics and experimental methods; and, for winning teams, the opportunity to conduct an experiment at a real accelerator facility.

Participation is team-based. The competition is open to secondary-school students worldwide. Teams develop an experimental proposal explaining the scientific idea and what they would investigate using a particle beam. The 2026 edition received submissions from 89 countries. Previous research experience is not stated as a mandatory requirement, but strong interest in physics, teamwork and the ability to develop a sound experimental proposal are important.